Vitellogenins and v itellins of the Mediterranean field cricket, Gryllus bimaculatus: isolation, characterization and quantification

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Abstract
In the Mediterranean field cricket, Gryllus bimaculatus de Geer, two immunochemically distinct female specific proteins were identified in haemolymph (Vg I and II) and in vitellogenic oocytes (Vn I and II). The corresponding Vgs and Vns seem to be immunochemically identical. On polyacrylamide gels Vg I and II as well as Vn I and II could not be clearly separated because Vg I and Vn I produced broad bands. The Mrs of both Vgs and Vns are approximately 525 kD. Upon dissociation by sodium dodecyl sulphate the Vgs and Vns each yielded at least nine polypeptides in the range of 50–215 kD. Haemolymph Vg titres were determined by rocket immunoelectrophoresis. The time of first appearance of Vg is temperature‐dependent and correlates with the onset of Juvenile Hormone synthesis by the corpora allata. Peak values of Vg were 17 μg μl‐1 haemolymph in normal vitellogenic females. After ovariectomy, Vg appeared at the normal time, but then increased to about 55 μg μl‐1 haemolymph. Ovariectomy also resulted in an accumulation of Vg in the fat bodies. Enforced virginity did not affect the haemolymph Vg titre. In allatectomized or head‐ligated females no Vg/Vn was detectable. Topical application of 100 μg Methoprene onto head‐ligated females induced Vg synthesis, whereas injection of 20‐hydroxyecdysone did not induce Vg synthesis.